The Comic Book Heroes by Gerard Jones & Will
Jacobs
Encyclopedia of American Comics edited by Ron
Goulart
Encyclopedia of Comic Book Heroes Vol. 1-3 by
Michael Fleischer
Marvel: Five Fabulous Decades of the World's
Greatest Comics by Les Daniels
The Official Overstreet Comic Book Price
Guide by Robert M. Overstreet et al
Seduction of the Innocent by Frederic
Wertham.
This is the biggest of the reviews by far
Seduction of the Innocent Revisited by John
Fulce
The Superhero Women by Trina Robbins
Unfortunately a review of Slings & Arrows got erased by mistake. Until a new review is ready, the following should suffice: it's the single most useful guide to comics available.